Brown noise turns your brain off, white noise helps you study and blue noise helps you think creatively — or at least, that’s what some influencers on social media will try to tell you.
Sonic hues, more generally known as coloured noise, is a term used to describe different frequencies of sound and site like YouTube are full of videos playing different frequencies that make all sorts of claims on what these noises do for your brain.
But there’s not a lot of scientific evidence for many of the claims. In fact, there aren’t even solid definitions of the different “coloured” noises.
Coloured noise generally refers to different frequencies on the sounds spectrum, using the analogy of the light spectrum.
When the human eye is presented with the full spectrum of visible light, we see white, so the idea is that when the human ear is presented with the full spectrum of noises we can hear — which is between 20 and 20,000 hertz for a healthy young adult — that noise is “white”, and every other noise gets a colour label depending on what frequencies it contains.
But as Associate Professor Wayne Wilson, from the School of Health and Rehabilitation Sciences at the University of Queensland says, it’s not as straightforward to define soundwaves.
“The problem with the analogy is that … we have those hard cut-offs in the visual spectrum, [but] we don’t have similarly hard cut-offs in the auditory spectrum,” he says.
“There’s no agreed-upon standard to say, brown noise is noise that contains frequencies from X to Y. People might claim there are standards, but there’s certainly nothing in the scientific literature or the technical literature that gives us hard standards.”
As well as there being no agreed standards for different colours of noise, what you use to play audio on can make a big difference to what you hear, with the same sound played through a small Bluetooth speaker being heard very differently to when it’s played through a high-end surround sound system.
And while a healthy, young adult with no hearing problems should be able to detect noises from between 20 to 20,000 hertz, many of us start to lose the ability to hear the full spectrum of sounds as we age, even without damaging our ears through too many loud concerts, or playing videos games with the sound on full blast.
Can noise affect us?
White noise is the most studied of the sound spectrum and it seems there is some truth to some of the social media claims.
White noise is a stochastic noise, meaning the frequencies in it happen at random in a way the brain can’t predict, unlike the noises in a piece of music that we can learn and anticipate what comes next.
“Stochastic noise is a special kind of noise. When we play stochastic noise to the brain, we think it does some special things,” Professor Wilson says.
For example, research done at the University of Queensland of students learning made-up alien names found that the students who heard the names with a background of white noise had better recall than the students who heard the names in silence.
Dr Wilson says it suggests that adding white noise can help the brain perform tasks such as learning new words, remembering things and certain problem solving.
Dr Wilson says white noise has not been found to improve performance in all cognitive tasks for all people, but the current science does suggest white noise can be particularly beneficial for people with attention deficits.
